The influence of pressure controlled reperfusion on the postischemic outcome of normal and normotensive hypertrophied rat hearts should be investigated. To induce normotensive cardiac hypertrophy, male Wistar rats received injections of isoprenaline (5 mg/kg s.c. bid for three days). Hearts were excised and perfused in the Langendorff-technique at a perfusion pressure of 75 mmHg for 30 min. After cardioplegia and 40 min of global ischemia at 25 degrees C the hearts were reperfused for 45 min. Reperfusion pressure was built up either abruptly (75 mmHg immediately) or gradually (from 40 mmHg to 75 mmHg within 30 min). Postischemic recovery was significantly affected by the mode of reperfusion in normal hearts where pressure controlled (gradual) reperfusion is superior to the abrupt reperfusion mode. In hypertrophied hearts the postischemic outcome did not differ from normal hearts if abrupt reperfusion was used, but gradual reperfusion only led to a comparably small amelioration of postischemic status.